Devices, systems and methods for endovascular temperature control

ABSTRACT

Devices, systems and methods for controlling a patient&#39;s body temperature by endovascular heat exchange.

FIELD OF THE INVENTION

The present disclosure relates generally to the fields of medicine andengineering and more particularly to devices, systems and methods forcontrolling a patient's body temperature by endovascular heat exchange.

BACKGROUND

Pursuant to 37 CFR 1.71(e), this patent document contains material whichis subject to copyright protection and the owner of this patent documentreserves all copyright rights whatsoever.

In various clinical situations, it is desirable to warm, cool orotherwise control the body temperature of a subject. For example,hypothermia can be induced in humans and some animals for the purpose ofprotecting various organs and tissues (e.g., heart, brain, kidneys)against the effects of ischemic, anoxic or toxic insult. For example,animal studies and/or clinical trials suggest that mild hypothermia canhave neuroprotective and/or cardioprotective effects in animals orhumans who suffer from ischemic cardiac events (e.g., myocardialinfract, acute coronary syndromes, etc.), postanoxic coma aftercardiopulmonary resuscitation, traumatic brain injury, stroke,subarachnoid hemorrhage, fever and neurological injury. Also, studieshave shown that whole body hypothermia can ameliorate the toxic effectsof radiographic contrast media on the kidneys (e.g., radiocontrastnephropathy) of patients with pre-existing renal impairment who undergoangiography procedures.

One method for inducing hypothermia is by endovascular temperaturemanagement (ETM) wherein a heat exchange catheter is inserted into ablood vessel and a thermal exchange fluid is circulated through a heatexchanger positioned on the portion of the catheter that is inserted inthe blood vessel. As the thermal exchange fluid circulates through thecatheter's heat exchanger, it exchanges heat with blood flowing past theheat exchange in the blood vessel. Such technique can be used to coolthe subject's flowing blood thereby resulting in a lowering of thesubject's core body temperature to some desired target temperature. ETMis also capable of warming the body and/or of controlling bodytemperature to maintain a monitored body temperature at some selectedtemperature. If a controlled rate of re-warming or re-cooling from theselected target temperature is desired, that too can be accomplished bycarefully controlling the amount of heat added or removed from the bodyand thereby controlling the temperature change of the patient.

SUMMARY

In accordance with the present disclosure, there are provided heatexchange devices, systems and methods which facilitate efficientendovascular and/or body surface heat exchange.

In accordance with one embodiment, there is provided a system forcirculating a warmed or cooled thermal exchange fluid through anendovascular heat exchanger (e.g., an endovascular heat exchangecatheter), wherein a) the system produces a pulsatile flow of thermalexchange fluid and b) the system is connected to the endovascular heatexchanger by way of one or more conduits which comprise a pulse dampingconduit that functions not only as a conduit through which the thermalexchange fluid flows but also a pulse damper for damping pulses orpressure in the thermal exchange fluid as it flows therethrough. Thepulse damping conduit may comprise, for example, tubing that hassufficient elastic or flexural properties to dampen or reduce theamplitude of pulses in the thermal exchange fluid as it flowstherethrough.

In accordance with another embodiment, there is provided a system forwarming or cooling the body of a human or animal subject, such systemcomprising an extracorporeal control system that is connectable to oneor more changeable component(s) (e.g., an endovascular heat exchangecatheter, a body surface heat exchange pad, tubing, a cassette throughwhich thermal exchange fluid circulates, other disposable components,etc.). When the changeable component(s) is/are connected to theextracorporeal control system, the system is useable to effect heatexchange with the subject's body. The changeable component(s) mayinclude machine readable encoded information. The extracorporeal controlsystem includes a reader that receives and reads the encodedinformation. The extracorporeal control system uses such encodedinformation to identify, qualify, confirm or control the operation ofthe changeable component(s). The encoded information may be stored inany suitable electronic storage medium and may be embedded in a chip ormicrochip mounted on or in the changeable component(s). Examples of thetypes of encoded information that may be stored include but are notlimited to; unique identifier(s) for the changeable components (e.g.,manufacturer identification, part number, lot number, etc.), indicationsof whether the changeable component(s) have previously been used (e.g.,an encoded indication of first use), indications of whether thechangeable component(s) is/are expired (e.g., encoded expiration date),operational characteristic(s) of the changeable component(s) (e.g.,encoded indications of the size, type, volume, etc. of the changeablecomponent(s). Examples of the types of information storage that may beutilized include but are not necessarily limited to: non-volatile randomaccess memory (RAM), non-volatile flash memory, electrically erasableprogrammable read-only memory (EEPROM) or ferroelectric random accessmemory (FRAM). The extracorporeal control system may comprises acontroller (e.g., a processor) programmed to take one or more actions inresponse to the encoded information. For example, the controller may beprogrammed to determine whether the encoded information meets aprerequisite requirement and to proceed with warming or cooling of thesubject's body only if said prerequisite requirement is met.

In accordance with another embodiment, there is provided a thermalexchange engine for warming or cooling a thermal exchange fluid. Suchthermal exchange engine comprises thermal exchange plates or evaporatorswhich are alternately coolable by circulation of refrigerant through theplates and warmable by heaters positioned on or in the plates. Acassette receiving space is located between the temperature controlledplates and is configured for receiving a cassette or heat exchanger. Thecassette comprises a frame and an expandable vessel (e.g., a bag orother expandable fluid containing vessel). The expandable vessel isfillable with thermal exchange fluid, e.g., after the cassette has beeninserted into the cassette receiving space. Heat is thereby transferredbetween the refrigerant and the thermal exchange fluid or the heater(s)and the thermal exchange fluid. In some embodiments, outer surface(s) ofthe expandable vessel may be coated with a release material, coveredwith a layer of releasable material or otherwise treated or modified todeter sticking of the expandable vessel to the adjacent thermal exchangeplates. In some embodiments, surface(s) of the thermal exchange platesand/or surfaces of the expandable vessel or a layer on a surface of theexpandable vessel may be textured or provided with holes, groves orother surface features to deter sticking of the expandable vessel to theadjacent thermal exchange plates. In some embodiments, the cassette maycomprise a housing attached to an insertable portion (e.g., the frameand expandable vessel) by a hinged attachment such that the cassette maybe disposed in a folded or closed configuration prior to use andconverted to an unfolded or open configuration at the time of use. Suchhinged connection between the housing and the insertable portion may beconstructed so that, once unfolded or opened, the cassette locks in theunfolded or open configuration. In some embodiments, a plurality ofhooks located in the console or system may be initially positioned inretracted positions allowing insertion of the instertable portion intothe cassette receiving space between the thermal exchange plates and,thereafter, may be moved to advanced positions wherein they hold theinsertable portion of the cassette within the cassette receiving space.

In accordance with another embodiment, there is provided a systemconfigured to circulate warmed or cooled thermal exchange fluid througha body heat exchanger to warm or cool the body or a human or animalsubject, wherein the system comprises a first display device whichreceives signals from one or more temperature sensors and displaystemperature data based on signals received from said one or moretemperature sensors. The first display device is connectable, by wiredor wireless connectivity, to a second display device (e.g., a bedsidemonitor, central unit monitor, remote monitor, etc.), so as to transmitsaid signals received from said one or more temperature sensors from thefirst display device to the second display device. The system furthercomprises circuitry for minimizing or eliminating any effect of ambienttemperature on such signals as they are transmitted from the firstdisplay device to the second display device. In some embodiments, thesignals transmitted from the first display device to the second displaydevice may comprise signals representative of sensed temperatures, suchas patient body temperature, temperature of thermal exchange fluidflowing to the body heat exchanger, temperature of thermal exchangefluid flowing from the body heat exchanger, etc.

Still further aspects and details of the present invention will beunderstood upon reading of the detailed description and examples setforth herebelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description and examples are provided for thepurpose of non-exhaustively describing some, but not necessarily all,examples or embodiments of the invention, and shall not limit the scopeof the invention in any way.

FIG. 1 shows one embodiment of an endovascular heat exchange systemcomprising an endovascular heat exchange catheter, an extracorporealcontrol console and a tubing/cassette/sensor module assembly useable foroperatively connecting the heat exchange catheter to the controlconsole.

FIG. 2A is a left/front perspective view of the control console with itsaccess cover in an open position.

FIG. 2B is a left/rear perspective view of the control console.

FIG. 3 is an exploded view of the control console with its access coverin an open position and the tubing/cassette/sensor module assemblystaged for insertion in, and operative connection to, the controlconsole.

FIG. 4 is a top (perspective) view of the control console with itsaccess cover in an open position and the tubing/cassette/sensor moduleassembly operatively inserted in and connected to the control console.

FIG. 5 is a top (plan) view of the control console with its access coverin an open position and the tubing/cassette/sensor module assemblyoperatively inserted in and connected to the control console.

FIG. 6 is a right/front perspective view of the control console with itshousing and access cover removed.

FIG. 7 is a left cross-sectional view of the control console.

FIG. 8 is a top cross-sectional view of the control console.

FIG. 9 is a right cross-sectional view of the control console.

FIG. 10 is a perspective view of a thermal exchange engine component ofthe control console.

FIG. 11 is a bottom/perspective view of a thermal exchange plateassembly of the thermal exchange engine.

FIG. 12 is a top/perspective view of the thermal exchange plateassembly.

FIG. 13 is a top (plan) view of the thermal exchange plate assembly ofthe thermal exchange engine.

FIG. 14 is disassembled view of one of the thermal exchange plates ofthe thermal exchange plate assembly, exposing a vertically orientedserpentine refrigerant flow path formed in the inner surface of theplate.

FIG. 15 is a rear view of the thermal exchange plate assembly with theouter plate and heater removed.

FIG. 16 is a partially disassembled rear perspective view of with thethermal exchange plate wherein rear plates have been removed so as toexpose secondary fluid flow channels useable for optional non-cassettewarming/cooling of a fluid.

FIG. 17 is a top view of the fully assembled thermal exchange plateassembly.

FIG. 18 is a schematic diagram illustrating the functional lay out ofthe thermal exchange engine.

FIG. 19 is a front perspective view of the pump assembly ofextracorporeal control console.

FIG. 20 is a partially disassembled view of the pump assembly whereinthe cover has been removed.

FIG. 20A is a separate view of a barrel-shaped guide roller of the pumpassembly.

FIG. 21 is a top view of the pump assembly.

FIG. 22 is a rear perspective view of the pump assembly disposed in anoperative configuration.

FIG. 23 is a rear perspective view of the pump assembly disposed in aloading configuration.

FIG. 24 is a rear perspective view of the tubing/cassette/sensor moduleassembly of the endovascular heat exchange system.

FIG. 25 is a front perspective view of the tubing/cassette/sensor moduleassembly.

FIG. 26 is a side view of the cassette and pump tubing portions of thetubing/cassette/sensor module assembly disposed in an open/lockedconfiguration useable for insertion and operation.

FIG. 27 is a rear perspective view of the cassette and pump tubingportions of the tubing/cassette/sensor module assembly disposed in aclosed configuration prior to insertion and operation.

FIG. 28 is a cross sectional view of the cassette portion of thetubing/cassette/sensor module assembly.

FIG. 29 is an exploded view of the sensor module portion of thetubing/cassette/sensor module assembly.

FIG. 30 is a schematic diagram of an endovascular heat exchange system.(convert to black/white formalize)

FIG. 31 is a schematic diagram of a heat exchange system capable ofproviding endovascular and/or body surface heat exchange. (convert toblack/white and formalize)

DETAILED DESCRIPTION

The following detailed description and the accompanying drawings towhich it refers are intended to describe some, but not necessarily all,examples or embodiments of the invention. The described embodiments areto be considered in all respects only as illustrative and notrestrictive. The contents of this detailed description and theaccompanying drawings do not limit the scope of the invention in anyway.

FIG. 1 shows one embodiment of an endovascular heat exchange system 10in operation to control the body temperature of a human subject. Thisendovascular heat exchange system 10 generally comprises an endovascularheat exchange catheter 12, an extracorporeal control console 14, atubing/cassette/sensor module assembly 60 or cassette assembly whichfacilitates connection of the catheter 12 to the control console 14 anda temperature sensor TS. In at least some embodiments, the catheter 12,tubing/cassette/sensor module assembly 60 or cassette assembly andtemperature sensor TS may be disposable items intended for a single use,while the control console 14 may be a non-disposable device intended formultiple uses.

In the embodiment shown, the endovascular heat exchange catheter 12comprises an elongate catheter body 16 and a heat exchanger 18positioned on a distal portion of the catheter body 16. Inflow andoutflow lumens (not shown) are present within the catheter body 16 tofacilitate circulation of a thermal exchange fluid (e.g., sterile 0.9%sodium chloride solution or other suitable thermal exchange fluid)through the heat exchanger 18. Optionally, the catheter shaft 16 mayalso include a working lumen (not shown) which extends through thecatheter body 16 and terminates distally at an opening in the distal endof the catheter body 16. Such working lumen may serve as a guidewirelumen to facilitate insertion and position of the catheter 12 and/or maybe used after insertion of the catheter 12 for delivery of fluids,medicaments or other devices. For example, as shown in FIG. 1, in someembodiments, the temperature sensor TS may be inserted through thecatheter's working lumen and advanced out of the distal end opening to alocation beyond the distal end of the catheter body 16. Alternatively,in other embodiments, the temperature sensor TS may be positioned atvarious other locations on or in the subject's body to sense the desiredbody temperature(s). Various heat exchange catheters may be used in theembodiments described herein. Non-limiting examples of heat exchangecatheters and related apparatus that may be used are described in U.S.Pat. No. 9,492,633, and United States Patent Application PublicationsNos. 2013/0090708, 2013/0178923, 2013/0079855, 2013/0079856,2014/0094880, 2014/0094882, 2014/0094883, and unpublished, copendingU.S. patent application Ser. Nos. 15/395,858, 15/395,923 and 15/412,390,the entire disclosure of each such patent and application beingexpressly incorporated herein by reference. Other examples of cathetersthat may be used in this invention include those commercially availablefrom ZOLL Circulation, Inc., San Jose, Calif., such as the Cool Line®Catheter, Icy® Catheter, Quattro® Catheter:, Solex 7® Catheter,InnerCool® RTx Accutrol Catheter and the InnerCool RTx StandardCatheter.

The extracorporeal control console 14 generally comprises a main housing20 and a console head 24. As described in detail herebelow, the mainhousing 20 contains various apparatus and circuitry for warming/coolingthermal exchange fluid to controlled temperature(s) and for pumping suchwarmed or cooled thermal exchange fluid through the catheter 18 toeffectively modify and/or control the subject's body temperature. Theconsole head 24 comprises a display device or user interface, such as atouch screen system, whereby certain information may be input by, andcertain information may be displayed to, users of the system 10. On thehousing 20 there are provided a first connection port 40 for connectionof a temperature sensor TS that is inserted through the heat exchangecatheter 12 as shown in FIG. 1 as well as other connection ports 36, 38for connection of additional or alternative types of temperature sensorsand/or other apparatus.

The tubing/cassette/sensor module assembly 60 or cassette assembly,which is seen in further detail in FIGS. 3-5, generally comprises asensor module 34, an inflow conduit 32, inflow connector 33, outflowconduit 30, outflow connector 31, temperature lead TL, temperature leadconnector 35, pressure lead PL, cassette 64, cassette housing 62 andperistaltic pump tubing 65.

FIGS. 2A through 9 show further detail of the components within thehousing 20 and the manner in which the tubing/cassette/sensor moduleassembly 60 or cassette assembly is inserted in and connected to thecontrol console 14. As seen in FIGS. 2A through 3, the control console14 has an openable/closable access cover 42 which, when opened, permitsinsertion of the cassette 64 into a cassette receiving space 66 as wellas other connection of the tubing/cassette/sensor module assembly 60 orcassette assembly to other components of the system described below. Amagnet 44 on the access cover 42 interacts with a magnetic sensor 46 toemit signal(s) indicating whether the access cover 42 is opened orclosed. Other sensors and detection mechanisms known to persons havingskill in the art may be utilized as well. The system controller locatedin the housing 20 may be programmed to halt running of certaincomponents of the system when the access cover 44 is opened. On the rearof the housing 20, there is provided a power switch 50 and a power cordholder 52. A bracket 48 is provided on an upstanding portion of thehousing which supports the console head 24 for hanging a bag orcontainer of fluid.

As seen in FIGS. 3 through 5, with the access cover 42 in an openposition, the cassette 64 is insertable downwardly into the cassettereceiving space 66 and the pump tubing 65 is insertable into a tubingraceway 72 of pump 70.

FIGS. 6 through 10 provide partially disassembled and sectional viewswhich reveal various components of the control console 14. The thermalexchange engine 108, includes a refrigeration system which comprises acompressor 92, stepper motor for turning an expansion valve 106, fans 96and 104, condenser 98 and compressor heat sink 100. The heat sink may bea metallic, e.g., aluminum, cylindrical enclosure that surrounds thecompressor. The heat sink is in contact with the compressor andincreases the surface area of the compressor to facilitate enhancesremoval of heat from the compressor. The thermal exchange system ispowered by power supply 94. Thermal exchange plates 80, are provided toalternately warm or cool thermal exchange fluid as it circulates througha cassette 64 that has been inserted in the cassette receiving space 66between the thermal exchange plates. Resistance heaters 82 are mountedon the plates 80 for warming the plates 80 when operating in a warmingmode and a refrigerant, such as Refrigerant R143a (1,1,1,2Tetrafluoroethane) is compressed by the compressor 92 and circulatedthrough the condenser 98 and plates 80 to cool the plates when operatingin a cooling mode. In certain embodiments, heaters may include a thermalcutout switch for automatically turning one or more of the heaters offif the heaters were to overheat.

When operating in a cooling mode, the thermal exchange engine 108 emitsheat. Fans 96 and 104 circulate air through air plenums or spacesadjacent to the thermal exchange engine 108 and over surfaces of thecompressor and compressor heat sink 100 to exhaust emitted heat andmaintain the thermal exchange engine 108 at a suitable operatingtemperature. Specifically, in the embodiment shown, air enters airintake 84 through filter 90, circulates through the device as indicatedby arrows on FIGS. 7 and 8, and is exhausted through an air outlet orexhaust vent on a side of the console 14 as shown specifically in FIG.8. The airflow pathway is specifically configured to minimize the amountof sound that escapes from the system via the airflow pathway and isaudible to a user or patient. The airflow pathway includes a convolutedpathway or channels which provide reflective surfaces to contain theacoustic energy within the cooling engine enclosure. Also, the interiorof the intake and exhaust ducts and pathway or channels are lined withan acoustically absorbent material, e.g., open-celled elastomeric foam.The combination of these features minimizes the amount of sound, such asthat generated by the fans and compressor, that escapes the system. Forexample, in certain embodiments, the operating noise level of a systemmay not exceed 65 dBA measured at a distance of 1 m from the system whenthe system is in maximum cooling and 58 dBA measured at a distance of 1m from the system when the system is in maintenance or warming.

The structure and function of the thermal exchange plates may beappreciated in further detail in FIGS. 11 through 17. Thermal exchangeplates 80 may be positioned on either side of the cassette receivingspace 66. The thermal exchange plates are connected on their endsforming a cassette receiving space or slot between the plates. Thethermal exchange plates may be referred to as a thermal exchange plateassembly. Resistance heaters 82 are mounted in one or more of plates 80and are useable to warm the plates 80 when warming of the circulatingthermal exchange fluid is desired. In certain embodiments, verticallyoriented, serpentine or convoluted, refrigerant flow channels 120 areformed within the plates 80. This orientation and design of therefrigerant flow channels help maximize and realize the cooling power ofthe cooling engine, e.g., For example, the plates are configured toevaporate the refrigerant moved by a 900 W compressor (e.g., aMasterflux compressor) within a cooling engine envelope sized to fitwithin the housing 20, as illustrated in the figures herein. In eachplate, cold refrigerant circulates through refrigerant inlet 112,through the refrigerant flow channels 120 and out of refrigerant outlet114. The refrigerant changes phase from a liquid substantially to a gaswhile flowing through the refrigerant flow channels 120, thereby coolingthe plates 80. Such warming or cooling of the plates 80, in turn causeswarming or cooling of thermal exchange fluid being circulated through acassette positioned within the cassette receiving space 66. Temperaturesensors 110, e.g., thermistors, may be located on the plates to detectthe temperature of the plates. Signals from the temperature sensors maybe fed back to the system controller or control processor to controlwarming and/or cooling (e.g., to prevent freezing) by the system.

Optionally, as shown in the views of FIGS. 15 and 16, the thermalexchange plates 80 may incorporate channels 125 for circulation of athermal exchange fluid directly through the plates. For example, adesired thermal exchange fluid may circulate in inlet 122, throughhorizontal flow channels 125 and out of outlet 124. A single inlet portmay be used to supply thermal exchange fluid to both plates as the fluidpasses from a first plate to the second plate, through channels locatedat the ends of the thermal exchange plate assembly, and exits thethermal exchange plate assembly through a single outlet port. A drainport 127 may be provided for draining residual thermal exchange fluid orflushing debris from the flow channels 125, when required. Thesechannels 125 may be used for cooling or warming a secondary thermalexchange fluid simultaneously with, or as an alternative to, the warmingor cooling of a heat exchange fluid circulating through a cassette 64inserted within the cassette receiving space 66. In some embodiments,the channels 125 may be configured to provide a volume flow of secondarythermal exchange fluid that differs from the volume flow of thermalexchange fluid which circulates through the cassette 64. For example, acassette 64 may be inserted in the cassette receiving space 66 and usedfor circulating a relatively small volume of warmed or cooled thermalexchange fluid (e.g., sterile saline solution) through an endovascularcatheter 12 and, simultaneously or alternately, the channels 125 may beused to warm or cool a larger volume of a secondary thermal exchangefluid (e.g., nonsterile water) for circulation through body surfacecooling device(s) such as surface cooling pad(s), blanket(s),garment(s), etc. Further details and examples of such concurrent orseparate use of endovascular and body surface temperature exchange aredescribed in copending U.S. patent application Ser. No. 15/412,390entitled Managing Patient Body Temperature Using Endovascular HeatExchange in Combination With Body Surface Heat Exchange, the entiredisclosure of which is expressly incorporated herein by reference.

A schematic diagram of an embodiment of a thermal exchange engine orrefrigeration loop useable in the systems described herein is shown inFIG. 18. This embodiment has a high side HS and a low side LS. Thecomponents shown in this diagram include superheat temperature sensor130, thermal exchange plate evaporators 132, electric heaters 134, anelectronic expansion valve, compressor 140, counterflow heat exchanger142, filter/drier sight glass 138, and electronic expansion valve 144.In the normal operational state of the cooling engine, the hot gasbypass valve 136 is closed, the compressor 140 is running, andrefrigerant flows through the system as follows. First, refrigerantexits the compressor in the gaseous phase at high pressure (typically8-14 bar) and high temperature (typically 100 to 130 degrees F.) andenters the condenser. In the condenser, heat is transferred from therefrigerant, causing it to condense into it's liquid phase and coolfurther (typically to 75-95 degrees F.). Liquid refrigerant then passesthrough the filter dryer 138 which filters the liquid for particulateand absorbs any water contained in the liquid. From there, liquidrefrigerant passes the sight glass “S” which allows an observer (e.g.service person) to confirm the refrigerant is in the liquid phase.Liquid refrigerant then passes through the primary channel of thecounterflow heat exchanger 142, which causes it to cool further(typically to 40-75 degrees F.) due to heat transfer with the secondarychannel of the counterflow heat exchanger. From there, liquidrefrigerant passes through the expansion valve 144, which acts as arestriction on the system. After passing through the expansion valve,refrigerant is suddenly at low pressure (typically 2-4 bar) and as aresult drops in temperature (to typically 25-35 degrees F.) andpartially enters the gaseous phase. Cold, low-pressure, liquidrefrigerant then enters the heat exchange plates 132. Heat is added tothe refrigerant from the following sources: from the thermal mass of theplates, from saline passing through the cassette heat exchanger, or fromwater passing through the liquid channels within the cold plates, all ofwhich cause the refrigerant to mostly or entirely enter the gas phase.From the heat exchange plates 132, low-pressure refrigerant flows intothe secondary channel of the counterflow heat exchanger where ittransfers heat from the refrigerant contained in the primary channel,causing it to warm (to typically 35 to 70 degrees F.). Refrigerant atthis point may be mostly or entirely in the gas phase, and then entersthe compressor 140, thus completing the circuit. A secondary operationalstate exists for the cooling engine, where the HGBP valve 136 is open.In this state, hot, gaseous refrigerant exits the compressor anddirectly enters the heat exchange plates, causing them to warm uprapidly. This secondary state is used when it is desirable to slow downthe cooling provided to the patient, or to warm the patient, withoutturning off the compressor. Alternatively, the compressor can be shutoff, however use of the HGBP valve 136 has the advantage of being ableto be opened and closed rapidly and repeatedly as necessary to maintainthe desired heat exchange plate temperature. One embodiment of a pump 70(e.g., a peristaltic pump) and associated assembly is shown in FIGS. 19through 23. The pump 70 comprises a rotor assembly 160 and cover 161connected to a drive motor 170 which causes the rotor assembly torotate. The rotor assembly includes guide rollers 164 a and 164 b, anddrive rollers 166 a and 166 b. As the rotor assembly rotates, duringpump operation, the drive rollers apply pressure to the pump tubing (notshown), which is positioned in the pump raceway, thereby causing thermalexchange fluid to move through the pump tubing. The pump raceway isdesigned with a low height (i.e. as measured along the axes of therollers) in order to allow the pump to be smaller, lighter weight, andlower cost. However with this low height it is critical to keep the pumptubing aligned with the raceway, in order to avoid jamming of the tubingwithin the pump assembly (leading to wear of the pump and wear orrupture of the tubing), and to avoid the tubing partially or entirelycoming out of contact with the drive rollers and thereby not generatingsome or all of the pressure needed to pump heat exchange fluid throughthe catheter. As seen in FIG. 20A, each guide roller 164 a, 164 b has atapered (e.g., barrel shaped) side wall 165. The guide roller mayinclude a central section which is not tapered (i.e. parallel to theaxis of rotation) 167. The tapered or barrel shape of the guide rollerfacilitates self-centering of the pump tubing on the guide roller, toensure that the pump continues to perform as intended. Because thetubing is being stretched over the guide rollers, a normal force isgenerated, which in turn creates a frictional force. The taper on therollers is at a shallow angle (e.g., of a range of 5 to 25 degrees) sothat the frictional force is sufficient to prevent the tubing fromsliding on the roller surface. Given that the tubing does not slide, thetaper or barrel shape puts a higher tensile load on the pump tubing atthe center of the roller (i.e. at the widest part of the barrel orroller), and a lower tensile load on the pump tubing at either the topor bottom edges of the roller (i.e. the narrowest part of the barrel orroller). This difference in tensile forces leads to the self-centeringeffect by developing a net force acting on the tubing along the axis ofthe roller, in the direction of the center of the roller. A frontportion of the pump 70 is mounted on a front plate 172. Optical sensors174, for detecting when a cassette 64 and its cassette housing 62 are inplace and properly positioned for operation, may also be located on thefront plate 172. Hooks 176 a, 176 b extend through slots in the frontplate 172. These hooks 176 a, 176 b are positionable in retractedpositions which allow installation of the cassette 64 and insertion ofthe pump tubing 65 in the pump raceway 162. Thereafter, these hooks 176a and 176 b are movable to advanced positions wherein they exert a forceon the cassette housing 62 at two separate points of contact therebydeterring unwanted movement of the cassette 64, cassette housing 62 orattached pump tubing 65, and securing the cassette in position forsystem operation. Also mounted on the front plate 172 are level sensorsfor sensing fluid levels within a reservoir formed within the cassettehousing 62. The pump 70 is alternately disposable in an operativeconfiguration (FIG. 22) and a loading configuration (FIG. 23).Translational motor 180 causes the hooks to move between a retracted andadvanced position, and causes the pump to move between an operative andloading configuration or position.

Priming of the system, when the cassette 64 is positioned in thecassette receiving space 66 between thermal exchange plates 80, may beperformed quickly by using one or more pump direction changes. The pump70 may be switched back and forth between running in reverse and runningin a forward direction for various durations of time, at various speeds.The first pump reversal creates a vacuum and the subsequent reversalshelp remove bubbles from the system/line.

To purge the thermal exchange fluid from the system the pump 70 may berun in reverse. In one example, the pump 70 may be run in reverse at 60%of max pump speed for about 20 seconds, during which the return line orvessel outlet line is closed to prevent the cassette vessel/bag fromrefilling with thermal exchange fluid or saline when the pump isreversed or opened. A check valve may be utilized, which may bepositioned in the cassette housing, e.g., in the vessel outlet tubing,between the tubing and the reservoir, to prevent the vessel/bag fromrefilling with thermal exchange fluid or saline when the pump isreversed or open. For example, in some embodiments, the check valve maybe integrated into the inflow connector 206 seen in FIG. 28 to preventfluid from back-flowing into the vessel/bag 63 when the pump is reversedor open . . . .

FIGS. 24 through 28 show further details of the tubing/cassette/sensormodule assembly 60 or cassette assembly. The cassette housing 62 isattached to a frame 69 which supports the side edges of the expandablevessel or bag 63. A lower edge 63 a of the expandable vessel or bag issealed and may include a support. As seen in FIG. 28, the cassettehousing (bottom cover removed) 62 encloses a reservoir 206, pressuresensor 202, outflow connector 204 which is connected to thepulse-damping outflow conduit 30, inflow connector 206 which isconnected to return or inflow conduit 32. During system operation,thermal exchange fluid returns from the catheter, flowing through inflowconduit 32, through inflow connector 206, through vessel inlet tubing,into the expandable vessel or bag 63, through the expandable vessel orbag 63 from one side to the other as indicated by arrows on FIG. 28,exchanging heat with refrigerant flowing through the thermal exchangeplates, then out of the vessel through vessel outlet tubing, intoreservoir 206, through pump tubing 65, through outflow connector 204,through pulse-damping outflow conduit 30 and back to the catheter.Refrigerant flows through the refrigerant flow channels in the thermalexchange plates in a first direction, while thermal exchange fluid flowsthough the expandable vessel in a second direction that is substantiallyopposite the first direction. This counter flow of refrigerant andthermal exchange fluid helps maximize heat exchange between the twofluids.

To minimize the force required to insert or remove the Heat Exchange(Hx) Bag or vessel from the Cold Plates, several methods are describedbelow.

The frictional force between the Cold Plates and the Hx Bag may bereduced by adding coating to the surface of the Cold Plates that lowersits coefficient of friction. Possible coatings include Teflon orsimilar. The surface of the Cold Plates may be polished. A coating maybe added to the surface of the Hx Bag that lowers its coefficient offriction, e.g., materials that may be used include silicone, or similar(these can be brushed, sprayed, dipped, etc.)

In some embodiments, a layer (release layer or antifriction layer) ofmaterial may be placed over the outside surface of the Hx Bag whichlowers its coefficient of friction. Possible materials includeparalyene, HDPE (Triton), ePTFE, PTFE, FEP or similar. A low frictionsheet made of these materials may be used. In certain embodiments, afluoropolymer may be placed on the cold plates and use a urethane HX bagwith HDPE release layer on the bag. The HX bag may include an HDPErelease layer on each side of the bag with each layer and the urethanebag affixed to the cassette frame with pegs or clamps. Alternatively, asingle longer piece of HDPE release layer may be folded around the HXbag and then the bag and release layers are affixed to the cassetteframe with pegs or clamps

The pulse-damping outflow conduit 30 functions not only as a conduitthrough which the thermal exchange fluid flows but also a pulse damperfor damping pulses in the thermal exchange fluid as it flows through theoutflow conduit, to a catheter. Pulses may arise due to the nature ofthe pump used for the thermal exchange fluid. For example, in the caseof a peristaltic pump with two drive rollers, at certain times bothdrive rollers are in contact with the pump tubing, and at other timesonly one drive rollers is in contact with the pump tubing, depending onthe angular position of the pump rotor within the raceway. The thermalexchange fluid system volume suddenly increases when a roller from theperistaltic pump loses contact with the pump tubing as a normal part ofthe pump's rotation. This happens because a section of the pump tubingthat had been flattened, and had zero cross-sectional area, suddenlybecomes round and contains a non-zero cross-sectional area. The increasein system volume is approximately the cross-sectional area of the tubingin its round state multiplied by the length of tubing flattened by theroller. The pulse dampener should have enough flexibility to contractsuddenly and decrease its volume by approximately this amount in orderto dampen the pulse. For example, the volume gained by the pump tubingwhen a roller leaves contact with it may be 2 to 3 mL. Therefore it isdesirable for a pulse dampener to be able to decrease its volume by thisamount with a minimal change in system pressure. The pulse dampingconduit may comprise, for example, tubing that has sufficient elastic orflexural properties to dampen, attenuate or reduce the amplitude ofpulses in the thermal exchange fluid as it flows therethrough. Forexample, if the conduit is able to expand by a volume of 20 to 30 mLunder 60 psi of pressure, then it will be able to contract by 2 to 3 mLwhen the pressure drops by approximately 6 psi. The more compliant theconduit is, the smaller the pressure drop that occurs when the tubingcontracts, and therefore the better the conduit performs its dampingfunction. While a highly compliant tubing is desirable, at the sametime, the conduit should have sufficient mechanical strength to expandand contract by this amount repeatedly without rupture. For example if aperistaltic pump has two driving rollers, turns at 40 RPM, and aprocedure lasts for 12 hours, the conduit must withstand 57,600pulsation cycles. To balance these conflicting requirements, forexample, in certain embodiments, the length of the pulse damping conduitmay be about 90″ and could range between 20″ and 100″. The conduit maybe made of a low durometer polyurethane (Prothane II 65-70A) and have alarge ID at 0.25″ and could range between 0.15″ and 0.40″. The wallthickness of the conduit is about 0.094″ and could range between 0.06″and 0.25″.

As seen in FIGS. 26 and 27 the cassette housing 62 is connected to theframe 69 by a hinged connection 200. As packaged prior to use, thehinged connection 200 is in a closed configuration so that the housing62 and accompanying pump tubing 65 are folded over the cassette'sflexible vessel or bag 63 in the manner seen in FIG. 27. At the time ofuse, the hinged connection is moved to an open configuration causing thehousing 62 and accompanying pump tubing 65 to extend at a substantiallyright angle relative to the expandable vessel or bag 63, as seen in FIG.26. The hinged connection 200 locks in such open position so that thecassette 64 cannot be returned to the folded configuration seen in FIG.27 without removing, disrupting or altering the hinged connection 200.For example, the hinged connection may be unlocked or disengaged bysliding a hinge protrusion forward or backward within a hinge slot,thereby disengaging the lock.

Details of the sensor module 34 are shown in FIG. 29. The sensor modulecomprises upper and lower housing portions 302 a, 302 b which, incombination, form an enclosed housing. Within the housing there ispositioned an electronic storage medium 310 which holds encodedinformation. Examples of the types of encoded information that may bestored include but are not limited to; unique identifier(s) for thechangeable components (e.g., manufacturer identification, part number,lot number, etc.), indications of whether the changeable component(s)have previously been used (e.g., an encoded indication of first use),indications of whether the changeable component(s) is/are expired (e.g.,encoded expiration date), operational characteristic(s) of thechangeable component(s) (e.g., encoded indications of the size, type,volume, etc. of the changeable component(s). In this non-limitingexample, the electronic storage medium comprises electrically erasableprogrammable read-only memory (EEPROM). One example of how thecontroller may check to determine whether the components had previouslybeen used is by checking the EEPROM or other data storage medium 310 fora First-Use date. The First-Use date would be “EMPTY” if this is thefirst time the changeable component (e.g., the cassette assembly) hasbeen connected to a console 14. If the First-Use date is “EMPTY”, thecontroller will write the current date to the EEPROM's memory locationwhere the First-Use date will then be stored.

Also, within the housing of the sensor module 34, there are provided afirst temperature sensor (e.g., a thermistor) for sensing thetemperature of thermal exchange fluid flowing to the catheter 12 and asecond temperature sensor 300 b (e.g., a second thermistor) for sensingthe temperature of thermal exchange fluid returning from the catheter12. Signals from these first and second temperature sensors 300 a, 300b, as well as body temperature signals from the connected bodytemperature sensor TS and encoded data from the electronic storagemedium 310, are transmitted through temperature lead TL. A pressure leadPL, which carries signals from a pressure sensor that senses thepressure of thermal exchange fluid within the cassette tubing or console14, combines with the temperature lead TL, as shown, and the combinedleads are connected to the control console 14. In this manner, thecontroller in the console main housing receives signals indicating a)the encoded data from the electronic storage medium 310, b) subject bodytemperature, c) thermal exchange fluid temperature flowing to catheter,d) thermal exchange fluid temperature flowing from catheter and e)thermal exchange fluid pressure. The controller may be programmed to usethe encoded information and/or sensed temperatures and/or sensedpressure for control of the system 10 and/or for computation/display ofdata. For example, the controller may be programmed to use thedifference between the sensed temperature of thermal exchange fluidflowing to the catheter and the sensed temperature of thermal exchangefluid flowing from the catheter, along with the fluid flow rate or pumpspeed, to calculate the Power at which the body heat exchanger isoperating. Power may be calculated by the following equation:

Power (Watts)=(HE Fluid Temp OUT−HE Fluid Temp IN)·Flow Rate·CP

-   -   wherein:    -   HE Fluid Temp IN is the current measured temperature of heat        exchange fluid flowing into the heat exchanger 18;    -   HE Fluid Temp OUT is the current measured temperature of heat        exchange fluid flowing out of the heat exchanger;    -   Flow Rate is the measured or calculated flow rate of heat        exchange fluid through the heat exchanger; and    -   CP is the specific heat capacity of the heat exchange fluid.

Such Power may be displayed on the display or user interface 24. Also,the controller may be programmed to check and accept the encodedinformation from the electronic storage medium 310 before allowing thesystem 10 to be used for warming or cooling the body of the subjectand/or to adjust operating variable or parameters to suit operativecharacteristics (e.g., size, operating volume, type) of the catheter 14,cassette 64, temperature probe, tubing or other components. Thispre-check of the encoded information may occur in various sequences orprocesses. One example of a process by which this pre-check may occur isby the following steps:

-   -   1. User connects tubing/cassette/sensor module assembly 60 to        control console 14.    -   2. Console controller detects this connection. Such detection of        the connection may occur by the controller scanning the        temperature sensor channels, which will open channels when no        tubing/cassette/sensor module assembly 60 is connected but will        become non-open when a tubing/cassette/sensor module assembly 60        is connected. Alternatively, this could be done by the        controller polling the polling the pressure sensor in the        cassette 64 or the EEPROM in the sensing module 34 for a        response.    -   3. Controller establishes a secure communication session with        the EEPROM and reads its content. The EEPROM's content may be        encrypted such that it is readable only by a processor having a        secret key. In some embodiments, the EEPROM itself may be        encoded with a secret key such that the controller may establish        a secure session in connection with the sensing module 34.    -   4. In some embodiments, the EEPROM content may comprise the        following information, some or all of which must be checked and        verified/accepted by the controller before priming and operation        of the system 10 may occur:        -   a. Manufacturer ID (factory written)        -   b. Cassette part # (factory written)        -   c. Shelf-life Expiration date (factory written)        -   d. Lot # (factory written)        -   e. Expiration duration since first use (factory written)        -   f. First-Use date (written when the cassette is first            plugged into the console)

FIG. 30 is a schematic diagram of the endovascular heat exchange system10. This schematic diagram shows major components of the system 10,including the console 14, heat exchange catheter 12, thermal exchangeengine 108, console head/user interface 24, thermal exchange plates 80and cassette 64. Additionally, this schematic diagram includes othercomponents and functional indicators labeled according to the followinglegend:

FS FLOW, SALINE FW FLOW, WATER LS LEVEL, SALINE LW LEVEL, WATER PSRPRESSURE SWITCH, REFRIGERANT PS PRESSURE, SALINE S SWITCH TACHTECHOMETER TA TEMPERATURE, AIR TR TEMPERATURE, REFRIGERANT TPTEMPERATURE, PLATE TS TEMPERATURE, SALINE TW TEMPERATURE, WATER

To set up the system 10 a new tubing/cassette/sensor module assembly 60or cassette assembly is obtained and removed from its packaging and thecassette 64 is unfolded to the opened and locked configuration seen inFIG. 26. The access cover 42 of the control console 14 is opened. An“open” button is pressed on the touch screen user interface 24 causingthe pump 70 to shift to its loading configuration as seen in FIG. 23.The cassette frame 69 and expandable vessel or bag 63 are inserteddownwardly into the cassette receiving space 66 until the housing 62abuts front plate 172. The pump tubing 165 is inserted within the pumpraceway 162. The access cover 42 is then closed and a “close” button isdepressed on user interface 24 causing the pump 70 to shift to theoperative configuration (FIG. 22). The user then presses a “prime”button on user interface 24 to prime the system with thermal exchangefluid from a bag or other container that has been hung on bracket 48 andconnected to the system 10.

After the system has been primed, the catheter 12 is connected andinserted into the subject's body and the system 10 is operated to warmor cool the subject's body as desired.

FIG. 31 is a schematic diagram of an example of a heat exchange system10 a capable of providing endovascular and/or body surface heatexchange. The system includes all of the elements described in thesystem 10 of FIG. 30 and, like FIG. 30, includes labeling according tothe legend set forth above.

Additionally, this system 10 a includes a body surface heat exchangefluid circuit 400 such that the system can provide body surface heatexchange by circulating warmed or cooled heat exchange fluid through atleast one body surface heat exchanger 402 (e.g., a heat exchange pad,blanket, garment, etc.) Such operation of the body surface heat exchangefluid circuit 400 and body surface heat exchanger 402 may be performedin addition to or instead of endovascular heat exchange. The bodysurface heat exchange fluid circuit includes a fluid reservoir, a pump,a bypass valve, a vent valve, thermal exchange plates and a body surfaceheat exchange device, e.g., a pad. A fluid, e.g., water, is added to thefluid reservoir. When the bypass valve is closed to the vent valve andopen to the bypass line, fluid circulates from the pump, through thebody surface fluid chambers in the thermal exchange plates, thereservoir, the bypass valve, and back into the pump. This allows thevolume of fluid within the system to come to thermal equilibrium withthe thermal exchange plates, which may be useful in preparing the deviceto deliver temperature management treatment to the patient. In normaloperation, the bypass valve is open to the vent valve and the vent valveis closed, and fluid circulates from the pump, through the body surfacefluid chambers in the thermal exchange plates, through the reservoir,bypass valve, and vent valve, to the body surface heat exchange deviceand then back through the pump. To drain the body surface heat exchangedevice, the vent valve is opened which allows air into the circuit andprevents fluid from flowing from the bypass valve. This forces fluid outof the body surface heat exchange device to the pump. The pump is apositive displacement pump capable of pumping air or liquid through thebody surface fluid chambers in the thermal exchange plates, to thereservoir. The reservoir is open to ambient air (to allow excess air toescape the system if introduced by the draining process or normaloperation, or to accommodate changes in fluid volume due to thermalexpansion) and includes a fill port or drain. The circuit also includesbody surface heat exchange fluid temperature sensors to provide feedbackto the controller, and fluid temperature sensors and fluid flow sensorsfor use in power calculations. Although the invention has been describedhereabove with reference to certain examples or embodiments of theinvention, various additions, deletions, alterations and modificationsmay be made to those described examples and embodiments withoutdeparting from the intended spirit and scope of the invention. Forexample, any elements, steps, members, components, compositions,reactants, parts or portions of one embodiment or example may beincorporated into or used with another embodiment or example, unlessotherwise specified or unless doing so would render that embodiment orexample unsuitable for its intended use. Also, where the steps of amethod or process have been described or listed in a particular order,the order of such steps may be changed unless otherwise specified orunless doing so would render the method or process unsuitable for itsintended purpose. Additionally, the elements, steps, members,components, compositions, reactants, parts or portions of any inventionor example described herein may optionally exist or be utilized in theabsence or substantial absence of any other element, step, member,component, composition, reactant, part or portion unless otherwisenoted. All reasonable additions, deletions, modifications andalterations are to be considered equivalents of the described examplesand embodiments and are to be included within the scope of the followingclaims.

1. A system configured to circulate a thermal exchange fluid through anendovascular heat exchanger, wherein: the system comprises a pump whichproduces a pulsatile flow of thermal exchange fluid; and the system isconnected to the endovascular heat exchanger by way of at least onedelivery conduit that comprises a pulse damping conduit which causesdamping of pulses in the thermal exchange fluid as the thermal exchangefluid flows therethrough.
 2. A system according to claim 1 wherein thepulse damping conduit comprises tubing that has sufficient elastic orflexural properties to dampen or reduce the amplitude of pulses in thethermal exchange fluid as it flows therethrough.
 3. A system accordingto claim 1 further comprising: a cooler for cooling the thermal exchangefluid; a heater for warming the thermal exchange fluid; a cassettepositionable in relation to the heater and cooler such that said pumpwill cause thermal exchange fluid to circulate through the cassette andbe warmed by the heater or cooled; said at least one delivery conduitextending from the cassette and being connectable to the endovascularheat exchanger, and at least one return conduit extending from thecassette and being is connectable to the endovascular heat exchanger,whereby, when said at least one delivery conduit and said at least onereturn conduit are so connected to the endovascular heat exchanger,warmed or cooled thermal exchange fluid will circulate from thecassette, through said at least one delivery conduit, through theendovascular heat exchanger, through said at least one return conduitand back into the cassette.
 4. A system according to claim 3 wherein thepump comprises a peristaltic pump in combination with pump tubing whichis compressed by said peristaltic pump in a manner that causes thepulsatile flow of thermal exchange fluid.
 5. A system according to claim4 wherein the pump tubing is attached to and extends from the cassette.6. A system according to claim 3 wherein the heater and cooler comprisethermal exchange plates having a space therebetween within which thecassette is insertable.
 7. A system according to claim 1 wherein thecassette comprises a bag attached to a frame.
 8. A system according toclaim 7 wherein a plurality of thermal exchange fluid flow channels aredefined within the bag.
 9. A system according to claim 7 wherein the bagis lubricated to facilitate its insertion into and removal from saidspace.
 10. A system according to claim 7 wherein holes, grooves or othersurface features formed in the bag to facilitate its insertion into andremoval from said.
 11. A system according to claim 3 wherein the pulsedamping conduit extends substantially the entire distance from thecassette to the endovascular heat exchanger, when connected to theendovascular heat exchanger.
 12. A system according to claim 11 whereinthe delivery conduit is at least 80 inches in length.
 13. A systemaccording to claim 1 wherein the pulse damping conduit is between 20inches and 100 inches in length, has an inner diameter between 0.15inches and 0.40 inches and a wall thickness between 0.06 inches and 0.25inches.
 14. A system according to claim 3 wherein: the cassettecomprises a cassette housing coupled to a vessel that contains thermalexchange fluid; and a check valve is positioned in the cassette housingto allow thermal exchange fluid to flow from the vessel into thecassette housing but to prevent thermal exchange fluid from backflowingfrom the cassette housing into the vessel.
 15. A system according toclaim 14 wherein: the pump runs in a forward mode for at least some ofthe time during set up or operation of the system; in at least someinstances, the pump also runs in a reverse mode for a period of timeduring set up or operation of the system; and wherein the check valvedeters backflow of thermal exchange fluid from the cassette into thevessel when the pump is running in reverse mode.
 16. A system accordingto claim 15 wherein the system further comprises a bubble detector andthe pump runs in reverse mode in response to detection of a bubble bythe bubble detector. 17.-82. (canceled)
 83. A system configured tocirculate a thermal exchange fluid through an endovascular heatexchanger, said system comprising: a reservoir that is fillable with thethermal exchange fluid; a delivery conduit through which thermalexchange fluid may flow from the reservoir to the endovascular heatexchanger, a return conduit through which the thermal exchange may flowfrom the endovascular heat exchanger to the reservoir; and wherein atleast a portion of the delivery conduit comprises a pulse dampingconduit that is configure d to dampen pulsations in the thermal exchangefluid as it flows therethrough.
 84. a system according to claim 83wherein the pulse damping conduit is at least 80 inches in length.
 85. Asystem according to claim 83 wherein the pulse damping conduit isbetween 20 inches and 100 inches in length, has an inner diameterbetween 0.15 inches and 0.40 inches and a wall thickness between 0.06inches and 0.25 inches.
 86. A system according to claim 83 wherein thereservoir comprises a cassette through which the thermal exchange fluidcirculates.
 87. A system according to claim 86 further comprisingapparatus for warming or cooling the thermal exchange fluid as itcirculates through the cassette.
 88. A system according to claim 83further comprising a pump which circulates thermal exchange fluid fromthe reservoir, through the delivery conduit, through the endovascularheat exchanger, through the return conduit and back into the reservoir.